With the miniaturized capabilities afforded by the discovery of solid state electronics, various improved means of dissipating the heat generated by solid state components have been investigated. The standard forced air convection means appears to have reached its's limit of practicality in that the amount of air that is required to provide sufficient cooling for the limited heat dissipating surfaces introduces a noise problem, and without some auxiliary techniques cannot maintain each of a large number of components within it's critical, narrow operating temperature range. Accordingly, especially in connection with large scale computer systems, various combinations of air-liquid cooling systems have been devised. One of the more recent systems investigated has been the immersion cooling system, wherein the array of components to be cooled is immersed in a tank of cooling liquid. The liquids used are the new fluorocarbon liquids which have a low-boiling point. These liquids are dielectric and give rise to various types of boiling at relatively low temperatures. In view of the problems encountered in servicing and packaging components which are cooled using this immersion technique, an encapsulated cooling technique was devised which includes the same dielectric material encapsulated separately for each module. U.S. Pat. No. 3,741,292, issued June 26, 1973 shows an example of a module having the heat generating components located thereon surrounded by a low boiling point dielectric liquid which is encapsulated thereto. A vapor space is located above the liquid level, which is filled with internal fins extending into the container serving as a condenser for the dielectric liquid vapors. External fins extend outward from the container and serve as an air cooled sink for the internal fins condenser. However, this type of a modular liquid encapsulated cooling device must meet certain inflexible requirements. For instance, it requires coolant of extremely high purity and free of any contaminants. It's operation is sensitive to all the variables which govern the basic process of nucleate boiling and vapor condensation. Furthermore, the concept is not readily adaptable to small scale applications such as a single heat generating component.
Accordingly, it is the main object of the present invention to provide an encapsulated cooling unit which utilizes inert gas having good thermal conductivity as the encapsulated medium in combination with a conductive heat transfer arrangement.
It is another object of the present invention to provide encapsulated inert gas having good thermal conductivity and having a low molecular weight so that it fills the heat transfer interfaces thereby providing a low thermal resistance path.
It is a further object of the present invention to provide an encapsulated inert gas with good thermal conductivity and a heat conducting element combination for cooling, in which the element is urged against the heat generating component to decrease the thermal resistance of the interface.
It is a further object of the present invention to provide an encapsulated inert gas having good thermal conductivity and a heat conductive element combination in which the heat transfer is automatically regulated as a function of temperature.